How is the due date calculated? 5. How to calculate the expected date of delivery?

March 8, 2013 The expected date of delivery is calculated from the first day of the last menstrual period.

According to medical regulations, the expected date of delivery is calculated from the first day of the last menstrual period, and the total duration of the pregnancy is 280 days, with 10 gestational months (each gestation month is 28 days). Pregnant women give birth within 38-42 weeks of gestation, both at term. Since the length of each woman's menstrual cycle varies, it is normal for the estimated due date to differ from the actual due date by 1-2 weeks.

The main calculation methods are as follows:

1.Calculated based on the last menstrual period:

The month of the last menstrual date plus 9 or minus 3 is the number of months of the expected date of delivery; The number of days plus 7 is the expected date of delivery. For example, Ms. Zhang's last menstrual period was March 13, 2008, and her due date was about:

20 December 2008. Ms. Li's last menstrual period was May 28, 2008, and her expected date of delivery was about March 5, 2009, which can also be extrapolated from the first day of her last menstrual period to the 280th day.

2.Calculated based on the date of fetal movement:

If you can't remember the date of your last menstrual period, you can calculate it based on the date of the fetal movement. Usually fetal movements begin at 16-22 weeks after pregnancy. The calculation method is as follows: the day of fetal movement plus 20 weeks for primiparous mothers; In multiparous women, the day of fetal movement plus 22 weeks is added. (General).

3.Calculated from basal body temperature curve:

The last day of the low temperature segment of the basal body temperature curve is taken as the day of ovulation, and 264-268 days are extrapolated backwards from the day of ovulation, or 38 weeks are added.

4.Extrapolated from B-ultrasound examination:

The doctor can estimate the gestational age and calculate the expected date of delivery by measuring the biparietal diameter of the fetal head, the length of the head and hip and the length of the femur by doing B ultrasound (this method is mostly used as a doctor's B ultrasound examination and diagnosis).

5.Extrapolation from the time of the onset of ejection:

Morning sickness usually occurs at the end of 6 weeks of pregnancy, that is, 42 days after the last menstrual period, and the due date is calculated backwards to 280 days.

The expected date of delivery is: the first day of the last menstrual period plus 9 months and 1 week (280 days). True labor may occur within 2 weeks before and after the due date...

If your menstrual cycle is 28 days, the due date is February 5, 2013... Wishing you and your child good health.

Your last menstrual period is May 1, 2012, your due date is the month minus 3, the number of days plus 7, and your due date is February 8, 2013.

The expected date of delivery should be calculated from the first day of the last menstrual month, and the month plus 9 or minus 3 and the date plus 7 will be calculated so that the calculation is the blessing of your due date.

The due date is calculated based on the last menstrual period. Add 9 or subtract 3 from the month, and add 7 to the date to be the due date, and the due date is February 8, 2013.

The last menstrual period is counted as the day you have your normal period, if this is the day you menstruate, your due date should be 2013-4-6,

From the first day of the last menstrual period, the month is minus three, and the date is added by seven.

Count it on the day your last menstrual period comes.

Both lunar and solar calendars can calculate the expected date of delivery.

From the first day of the last menstrual period, the month is added by nine or minus three, and the number of days plus seven is the due date of the solar calendar.

From the first day of the last menstrual period, the month is added by nine or minus three, and the number of days plus 14 is the due date of the lunar calendar.

Suggestion: Actual delivery may occur within 2 weeks before and after the expected date of delivery.

If the menstrual period is not accurate, there may be some errors, if the menstrual period is short, the pregnancy period is appropriately advanced, and if the menstrual period is long, the pregnancy period is appropriately extended.

Under normal circumstances, the average woman will give birth after about 10 months of pregnancy, and the approximate time is about 40 weeks, so the patient first needs to know the time of his last menstrual period, starting from the first day of the last menstrual time, subtracting 3 from the month of the last menstrual period, and adding 7 to the date, so as to basically get the time of the normal due date of the woman, so as to be able to effectively prepare.